The microtoroid has demonstrated the detection of heavy water concentrations as low as 1ppmv (1 part per million per volume).  This is a 30x improvement over previous heavy water detection methods.

By testing in the visible, and thus reducing loss due to water absorption, the toroid has quality factors above 100 million in water.  This is a crucial step to the development of a biological or chemical microcavity sensor.

Caltech optics microcavity microtoroid microresonator array optical micro-cavity photonics optical fiber taper nanowire tapered optical fiber fluidics microfluidics biosensing chemical sensing optofluidics biological sensing sensor detection single molecule sensing ultra high Q quality factor H2O D2O heavy water